Most tumor cells contain abundant glycogen as revealed by PAS stains with and without diastase. Immunohistochemical studies reveal most tumor cells are distinctly positive for placental alkaline phosphatase. No immunoreactivity is observed in tumor cells for synaptophysin and HMB45. Only rare tumor cells stain for cytokeratin AE1/AE3 and none are positive with S100 staining.
DIAGNOSIS AND DISCUSSION